Automatic clutch



Jan. 19, 1937. F. KREIS AUTOMATIC CLUTCH Original Filed Feb. 4, 1955 I4@F/g. 9.

Patented Jan. 19, l1937 UNITED STATES PATENT OFFICE AUTOMATIC CLUTCHFritz Kreis, Nuremberg, Germany ber 7, 1933 9 Claims.

The invention relates to centrifugally operated automatic 'clutches formotor driven vehicles. Most of these clutches depend exclusively upon africtional engagement between the clutch members, some, however, haveprovided an additional automatic locking mechanism for obtaining apositive drive engagement in the higher speed ranges. One object of theinvention is to provide an automatic clutch of a very simple structurerequiring fewer parts and having centrigufally-operated clutch elementsbetween the drive and the driven member adapted to establish insuccession both a frictional and a. positive drive engagement betweenthe said members.

A further object of the invention is to provide an automatic clutchembodying a control mechanism to be actuated by the driver for lockingthe automatic operation of the clutch elements by bringing -same intopositive drive engagement with the clutch members and keeping them inthis position, so that the motor can be connected at any speed andpreferably at low speed with the driven shaft, to act as abrake.

A still further object of the invention is to provide an automatic freewheeling clutch having a gravity controlled mechanism for locking theclutch elements, when the vehicle moves downhill, so that in such eventindependent from the care of the driver the motor is positivelyconnected with the driven shaft to act as a brake.

Further features of the invention are the combination of the manuallyoperated and the gravity controlled mechanisms with each other and withthe brake and the motor controlling means, whereby all operations can becarried out by a single control lever or pedal.

Other features are hereinafter set forth and more particularly definedby the claims.

In the drawing Fig. 1 is a sectional view through a. clutch embodyingthe invention.

Fig. 2 shows the clutch one quarter in section on line 2-2 of Figf l andone quarter in elevaclined position.

Fig. 8 is a side elevation and Fig. 9 is a plan showing parts of thepedal mechanism according to Fig. 5 to an enlarged scale.

Referring to the drawing the numeral 2 designates the drive memberhaving a motor driven shaft portion 2a. The drive member 2 is a wheelhaving a number of radial spokes 5, for instance six spokes, with bores6 open to the outer periphery. In the bore of each spoke 5 a ball 8 issituated adapted to slide within the bore 6 of the spoke under theinfluence of centrifugal force when rotating together with the wheelbody 2. Outward movement of the balls 8 is resisted and accuratelyadusted by compression springs 9 arranged in the bores 6 of the spokes 5above the balls 8. Rings I0 are interposed between the inner ends ofthesprings 9 and the balls 8. 'Ihe outer ends of the springs 9 engage withrings II bearing against inwardly projecting flanges of sleeves I2,which are slidably mounted in the bores 6 near the periphery of thewheel body 2. The sleeves I2 possess flanges I 2a projecting at theirouter ends and lying between the outer circumference of the Wheel body 2and the inner face of a clutch lining I3 enclosing the wheel body 2. Thelining I3 is divided up over the whole of the periphery into sixsegments, each segment `contacting at each endvwith a flange I2a of thesleeves I2. The outer faces of the segments of the lining I3 are locatedwith small clearance within a surrounding drum wall Ida of a drivenwheel I4 having on the side a shaft portion 14h, which is rotatablymounted in bushes I9 and 20 provided in a central bore 2b of the wheelbody 2. On its opposite side the wheel I4 has an extension forming apinion 2| for engagement with a transmission gear or any other drivenpart not shown. Attached to the inner face of each segment of the liningI3 is a spring steel plate I5a, giving the segments a curved initialstressing (Fig. 3) for ensuring, that the ends of the segments readilypress on the flanges I2a of the sleeves I2 for balancing the centrifugalmasses at low speeds and that the whole of the lining vwill bear overits entire surface against the drum wall Ida'.

In each spoke 5 of the wheel body 2 the compression spring 9 surrounds astem I5 of a locking member I6, which is loosely guided by the ring I Ibut rigidly connected at the inner end to the ring I0. The lockingmember I6 adjoining the outer end of the stem I5 is slidable within thesleeve I2 and adapted to reach the inside of the drum wall Ida andengage in recesses Il provided in the same, so that a rigid connectionbetween the wheel body 2 andthe driven member I4 can be established.Each locking member I6 has an inclined flank Ilia on its rearward end indirection of rotation and the rear of each recess I1 is correspondinglyinclined at I1a. At its inner end the bore 6 of each spoke 5communicates with the central bore 2b of the Wheel body 2 through aradial bore 6a of smaller diameter lil/provided in the hub portion ofthe wheel body 2.

In each bore 6a a ball 'I is inserted contacting outwardly with the ball8.

The drivenV wheel I4 has a central bore 22Y extending from the pinion 2|to the middle shaft portion I4b of the wheel. In the bore 22 a push bar23 is slidably mounted, which carries on its inner end a transversedriving pin 24, extending through a longitudinal slot 25 in the middleshaft portion I4b. In the bore 22 a helical spring 26 is provided, whichexerts an outwardly directed pressure to the inner end of the push bar23. The ends of the driving pin 24 project on opposite sides from theperiphery of the shaft portion I4b and engage in corresponding bores ofa ring 21 mounted on the shaft portion I4b and axially slidable withinthe bore 2b of the wheel body 2 between the bush I9 and an innershoulder of the hub of the wheel body 2. The ring 21 has on one side aconical face contacting with the balls 1, so that by an axial movementof the ring 21 towards the right in Fig. 1, the latter are forcedoutwards into the bores 6 of the spokes.

The outer end of the push bar 23 extending from the pinion 2| ispivotally connected to the one arm of a two-armed lever 28, which ismounted so as to pivot with its middle part about a pin 29 xed to theframe of the vehicle or to the transmission casing. The opposite arm ofthe lever 28 is connected on its outer end by a link 30 with the arm 3iof a pedal 32, both mounted on a rotatable shaft 33. To the pedal shaft33 a further lever 34 is fixed, rotatable together with the shaft, whichis connected with a rod actuating the normal brakes` of the road wheels.

It will be obvious from the foregoing that on rotation'of the engine andof the wheel body connected therewith, the balls 8 are thrown out- Wardsby centrifugal force. They are thrown out further, the greater the speedof rotation of the wheel body. 'I'he centrifugal force of the balls actsfirst against the compression springs 9 andthe latter through the ringsII on the sleeves I2, whichl will then press against the clutch liningI3. Each segment of the lining I3 is pressed at each end by the flangeI2a of a sleeve I2 against the inside of the drum wall I4a taking withthe wheel body 2 by friction the driven gear wheel I4. The springs 9 arecompressed in proportion to the increase of the centrifugal force of theballs 8, which on their outward movement project the stems I of thelocking members I6, so that finally the latter will reach and engage inthe recesses I1 in the drum wall' Ila, so that a rigid connectionbetween the wheel body 2 and the driven member I4 isdenitelyestablished. An automatic clutch is thus provided which in the firstplace acting as a friction clutch starts `the driven member and which onincreasing speed of revolution provides a rigid driving connection ofthe clutch elements by centrifugal means. When the speed of revolutiondrops, the stressing of the springs 9 is released by the decrease in thecentrifugal force of the balls 8 and the locking members I6 will bewithdrawn by the springs into the spokes of the wheel body and finallythe pressure on the lining I3 will be relaxed. The driven member canthen rotate freely without any substantial friction.

through the link 30 and the swinging lever 28 to the push bar 28v whichis inwardly pressed against the action of the spring 26. The bar 23 onbeing pushed inwards transmits its longitudinal movement by means of theconnecting pin 24 to the conical ring 21 which moves to the right inFig. 1. By this movement the conical part of the ring 21 forces theballs 1 outwardly into the bores 6. By this means the balls 8 and thedriving members I6 are forced outwards and the latter are held in therecesses I1 of the driven wheel I4.

On releaseA of the pedal 32 the spring 26,011 expanding returns the ring21 and the other parts connected therewith into the former position andthe balls 1 are free to move inwards again, thus re-establishing thenormal working conditions of the centrifugal clutch. Through therotatingpedal shaft 33 and by means of the lever 34 the brake rods of the normalbrakes of the driving The control mechanism explained above ensures thatat any time and preferably when the engine is idling and the centrifugalforces are not sufcient for obtaining an engagement of thedrive and thedriven member a positive drive engagement can be established.

In Figs. 4-9 a modied constructional form of an automatic centrifugalclutch is illustrated, which embodies a locking mechanism for the clutchelements which is connected with controlling means to be operated by thedriver and further with an automatic control for actuating the lockingmechanism when the vehicle assumes a forward inclined position. Inpractice the control mechanism of the clutch will be operated by asingle pedal, which simultaneously is operable to control the throttleof the engine and 'also the normal brakes of the vehicle.

In Fig. 4 those parts of the clutch described above and shown in Figs. 13, which have been retained in the present form bear the same referencenumerals as before. According to the modiflcation centrifugally operatedballs 8m are fixed to the free ends of curved levers 8b which aremounted on pivots 8c fixed in slots of the spokes 5 near the hub of thewheel body 2. The free ends of the pivoting levers 8b with thecentrifugal balls a'extend through a common rearward opening 5a ofthewheel body 2. The upper edges of the levers 8b engage with 'groovesI0c provided in the spherical ends IIIa of sliding members IIlb guidedin the radial bores 6 and rigidly connected with the stems I5 of thelocking members I6. 'Ihe member IIlb possesses a greater diameter thanthe stem I5 and forms on the upper face adjoining the stem an abutmentfor the lower end of the helical spring 9, the upper end of whichcontacts with the sleeve I2. On the shaft extension 2a of the Wheel body2 a control sleeve |30 is slidably mounted having on one side a conicalface I 38a road wheels can .be simultaneously operated. 35'

adapted to engage with the vlower edges of the curved levers 8b and topress them radially outwards, when moved along the shaft extension 2ainto the opening a of the wheel body 2. On the levers 8b swingingoutwards under the influence downwardly extending levers |32, the upperends of which are xed to a rotatable shaft |33 extending transverselyabove the driving shaft portion 2a. At the one end of the shaft |33 alever |34 is fixed, which projects upwardly in oblique direction. Theupper end of the lever |34 is in contact with the lower cam face of aguide bar |35 forming part of a pedal lever |36. The pedal lever |36 ispivotally mounted on a rod |50 and the guide bar |35 is provided at acertain distance from the rod |50. A helical spring |41 is also providedon the pedal lever and normally acts to keep in or to return the leverto the inoperative position (Fig. 5). The cam face 'of the guide |35embodiestwo portions a and b of circular shape lying at differentdistances from the coinciding centre, represented by the pivoting point|50, and the two portions are connected by an inclined surface 31.

On operation of the pedal lever |36 the guide bar |35 turns togetherwith the said lever about the rod |50 thereby acting on the lever |34,which can assume two different positions. On the portion a o1 the camface sliding along the lever |34, the latter remains stationary, whileup to the point where it reaches the portion b the lever 34 must slideover the inclined surface |31, during which it is turned and imparts arotary motion to the shaft |33. On the shaft |33 being turned,

the movement is transmitted by the swinging levers |32 and the stirrup|3| to the control sleeve |30, which iscausedto slide along the shaft2athereby pressing the levers 8b and the locking members.|6 connectedtherewith outwardly, so that the latter engage with the recesses |'lthereby establishing a positive drive connection between the drive andthe driven member. Thus along operation of the clutch can take placewhile along the portion -b the clutch elements are locked in theoperative position. f

The pedal lever |36 is also operable to control the throttle oftheengine. For this purpose a lever |38 is fixed to the pedal lever |36which projects from the pivoted end of the said lever and moves togetherwith same. The free end of the lever |38 contacts with the free end of asecond lever |39-which is independently pivoted on a shaft 40. Bothlevers |38 and |39 are arranged with respect toeach other in such a waythat they can be released after a certain path of travel. The lever|39is loosely journalled on the shaft |40 and possesses a recess |39a inthe hub portion enclosing the said shaft, which engages with the pin |4|projecting from the shaft M0. By this arrangement the lever |39l is freeto turn on the shaft to a.. certain degree. `Further a helical spring|45 is fixed to the lever |39, which exerts a downwardly directedtension on the said lever and thereby keeps the one end of the recess|39a in contact with the pin |4|. A second lever |42 is rigidlyconnected withthe shaft |40.and adapted to be turned with the same. Thefree end of the lever |42 is connected with the throttle by a rod |43. Ahelical'spring 44 is secured to the lever |42 and exerts a tension inhorizontal forward direction (Fig. 5 and Fig. 8). 'I'he pedal lever |36possesses a further joint at the rear end of the guide bar |35, which isconnected with the brakes by a rod |46.

On operation of the pedal lever |36 the rod |43 for the throttle viscontrolled while the portion a of the cam face slides along the lever|34. During this movement the lever |38 rotates together with the pedallevervin a clockwise direction and presses on the end of the lever |39.On its movement the lever |39 turns the shaft |40 by means of theslot-and-pin connection in an anticlockwise direction, thereby alsoturning the lever |42 which acts on the throttle of the engine. The pathtravelled vby the lever |39 gives the exact fuel supply from zero tomaximum and after the maximum point 'has been reached the end of thelever |39 is released from the lever |38 and the latter is caused by thespring |44 of the lever |42 and by means of the pin-and- Slot connectionwith the shaft |40 to return into its initial position. For enabling thelever |38 of the pedal to engage in its return motion over the lever|39, the latter is journalled on the shaft 40 so as to turn loosely inthe backward rotary direction. The spring |45 causes the lever |39 to bebrought into its correct zero positon. Thus, the fuel supply is broughtto its maximum as long as the lever |34 rides on the portion a of theguide bar |35. On the lever |34 being rocked through the inclinedportion |31 of the guide bar, y

whichcorresponds to a movement of the clutch elements into the operativepositon, the maximum point of the throttle is reached and the throttleno longer allows fuel to reach the engine. On the pedal being furtherdepressed the lever |34 will ride on the portion b of the guide bar |35.Along the portion b the clutch elements are always operative. 'I'hisportion can, however, be utilized for operating the brake rod |46leading to the driving wheels. The spring |41 returns the pedal lever|36 again into its original position when it is released. By thisarrangement therefore the vehicle can be started and stoppe-d with onepedal. This is of specialimportance in cases of danger, as it is nolonger necessary for the foot to seek the correct pedal, all that isnecessary being completely to depress the accelerator pedal Iand thevehicle will then slow down.

In steep downward gradients the locking mechanism of the clutch will beautomatically operated. For this purpose a weight |48 is suspended in aregulable manner on a downwardly directed slot |5| and contacts on oneside with the free end of the lever |52 whereby it is possible to setthe lever |49 to a certain inclination with respect to the verticalline.

On the vehicle assuming a forward inclined position owing to thegradient, the lever |49 will be turned through theforce of the weight|48 about its pivot |5ll. On the weighted lever |49 turning, the lever|52 engaging with the slot |5| in the upper'arm of the lever |49, an-dwith it the shaft |33 will also be turned, which brings the clutchelements into operation in the above explained manner. When the vehicleis on level ground the angle a of the lever |49 to the horizontal line(Figs. 5 and 7) will amount to 90. On the vehicle becoming more and moreinclined forwards on a downward gradient, the `angle a will becomesmaller and smaller and the angle of inclination ,s correspondinglygreater. By means of the adjusting screw |53 a desired angle ofinclination can be quite accurately set to a value from which the normalautomatic clutch operation will not be eifective. Preferably normalclutch operation will be allowed to remain operative in slight gradientsand be put out of operation only in the case of steep gradients. Bythismeans the reliability of the vehicle is increased very considerably.i

1. In a clutch the combination .of a driving member, a driven member, afriction lining between th'e two members, radially disposed guides inthedriving member, sliding sleeves in the said guides in contact withthe lining, locking members ,in the said sleeves adapted to engage thedriven member, means for .resisting the movement of the locking memberswith respect to the sleeves, centrifugal weights inthe driving member inengagement with the locking members and adapted to resiliently press thelining against the drivenfmember and to move subsequently the lockingmembers into engagement with the said driven ymember and means forindependently moving the centrifugal weights into the position ofpositive drive connection between the said members.

2. In a clutch the combination of a driving member, a driven member, a,friction lining between the two members, radially disposed guides in thedriving member, sliding sleeves in the said guides in contact with thelining, locking members in the Fsaid sleeves adapted to engage thedriven member, means for resisting the movement of the locking memberswith respect to the sleeves, centrifugal weights in the driving memberin engagement with the locking members and adapted to resiliently pressthe lining against the driven member and to move subsequently thelocking members into engagement with the driven member, a cam providedin the driving member adapted to engage with the centrifugal weights andto bring same into the position of positive drive connection between thesaid members and controlling means connected with the cam operable tobring same into and out of engagement with the centrifugal weights.

3. In a clutch the combination cfa driving member having radial spokesand a central bore, a driven member provided with a shaft extensionjournalled in the central bore of the driving meml ber, a frictionlining between the two members, guiding bores in'the said spokes,radially disposed bores in the driving member connecting the guidingbores with the central bore, sliding sleeves in the said guides incontact with the lining, locking members in the said sleeves adapted toengage the driven member, means for resisting the movement ofthe lockingmembers with respect to thesleeves, centrifugal balls in the guidingbores' radially movable outwardly in engagement` with the lockingmembers and adapted to resiliently press the friction lining against thedriven member and to subsequently-move the locking members intoengagement with the said driven member, a cam sleeve mounted axiallyslidable on the shaft extension of the driven member and in the centralbore of the driving member, pressure elements in the connecting boresand in contact with the centrifugal balls and the sleeve and controllingmeans connected with the sleeve operable to axially displace same intoand out of engagement with the pressure elements.

4. In a clutch the combination of a, driving shaft, a driving memberconnected with the said shaft having radial spokes 'and a central bore,a driven member provided with a shaft extension journalled in thecentral bore of the driving member, a friction lining between the twomembers, guiding bores in the said spokes, sliding sleeves in the saidguides in 4contact with the lining, locking membersguided in the saidsleeves and in the bores of the spokes, adapted to engage the drivenmember, means' for resisting the movement of the locking members withrespect to the I sleeves, weighted levers pivotally mounted in thespokes radially swingable outwardly in engage-l ment with the lockingmembers and adapted to resiliently press the friction lining against thedriven member and to subsequently move the Y locking members intoengagement with the said driven member, a cam sleeve axially slidable onthe driving shaft operable to engage with the weighted levers and to'press them radially outwardly into the position of" positive driveengagement of the drive and driven members Aand controlling meansconnected with the sleeve and operable to axially displace same into andout of engagement with the weighted levers.

5. In a clutch the combination of a driving member, a driven member, afriction lining between the two members, radially disposed guides in thedriving member, locking members arranged in the guides, clutch weightsslidably mounted in the said guides operable to bring the lining intofrictional engagement with the driven member and to move the lockingmembers'into positive driving connection with the said driven member, acam provided in the driving member adapted to engage with thecentrifugal weights, a control shaft connected with the cam, a leverfixed to the control shaft, and a pedal lever separately mountednear thecontrol shaft and having a cam face engaging with the lever of thecontrol shaft and operable to turn same on movement of the pedal lever.

6. In a clutch for motor driven vehicles according to claim 5, the pedallever being operatively connected with the throttle of the engine.

7. In a clutch for motor driven vehicles according to claim 5, the pedallever being operatively connected with the brakes of the vehicle.

8. In a clutch according to claim 5 a further lever xed to the controlshaft, a double-armed lever pivotally mounted near the lcontrol shafthaving a, lower arm provided with 'an adjustable weight and an upper armprovided with a' slot engaging with the lever of the control shaft andoperable to turn same independently from the pedal lever. v

9. In a clutch the combination of a driving member, a driven member, afriction lining between4v the two members, radially disposed guides inthe driving member, locking members arranged in the guides, clutchweights slidably mounted in.

and a weighted lever pivotally mounted near the control shaft and havingan arm engaging with the lever of the control shaft and operable to turnsame on movement of the weighted lever.

FRITZ KREIS.

